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利用java servlet实现简单的web请求过滤和跳转

今日有两个微信web项目合并了,但是还有些链接指向废弃的项目,另外不想在服务器上运行两份相同web项目(1、影响性能、2、维护升级容易出错),因此决定写一个简单链接跳转的项目,spring的filter过滤器可以实现,但想想spring干这个有点大材小用,想到java的servlet可以支持通配符,因此用servlet写了一个简单的跳转程序,总共花了不到一小时的时间。废话少说上代码:

 1 /** 2  * Servlet implementation class Default 3  */ 4 @WebServlet("/*") 5 public class Default extends HttpServlet { 6     private static final long serialVersionUID = 1L; 7  8     /** 9      * @see HttpServlet#HttpServlet()10      */11     public Default() {12         super();13         // TODO Auto-generated constructor stub14     }15 16     /**17      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse18      *      response)19      */20     protected void doGet(HttpServletRequest request,21             HttpServletResponse response) throws ServletException, IOException {22         String thisURI = request.getRequestURL().toString();23         String queryString = request.getQueryString();24         String host = "112.125.121.163";25         //String host = "localhost";26         String oldURI = "http://" + host + ":8080/travel-core";27         if (thisURI.indexOf(oldURI) >= 0) {28             String newURI = thisURI.replaceAll(oldURI, "http://" + host29                     + ":8080/travel-weixin");30             if (queryString != null && queryString.length() > 0)31                 newURI += "?" + queryString;32             response.sendRedirect(newURI);33         }34     }35 36     /**37      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse38      *      response)39      */40     protected void doPost(HttpServletRequest request,41             HttpServletResponse response) throws ServletException, IOException {42         this.doGet(request, response);43     }44 45 }

注意代码第四行是关键@WebServlet("/*"),这里使用了通配符,所有的请求都会送到doGet和doPost方法里,另外要注意 request.getRequestURL()方法不能获取到queryString因此一定要request.getQueryString()获取参数,拼到新地址的后面。